Rotary electric switch



2, 1945- F. P. GATES 5,0

ROTARY ELECTRIC SWITCH Filed March 18, 1944 I T 1 0 T za //WA/rm FREDERIC P. GATES 57 ///J ATTORNEY) Patented Oct. 2, 1945 ROTARY ELECTRIC SNITCH Frederic P. Gates, Toronto, Ontario, Canada, as-

signor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn, a corporation of Connecticut Application March 18, 1944, Serial No. 527,082 In Canada January 3, 1941 Claims.

This invention relates to electric switches. More particularly it relates to a rotary electric switch construction useful generally, but particularly adapted for use in control of heating circuits of an electric range or the like.

It isan object of this invention to provide a simplified construction of slow-break rotary electric switch for control of heater circuits in alternating current circuits.

Other objects and advantages of my invention will become apparent as it is described in connection with the accompanying drawing.

In the drawing- Fig. l is a plan view of the base of an electric switch embodying the principles of my invention, with the cover removed therefrom.

Fig. 2 is a plan view of the bottom side of the cover for the switch base of Fig. 1.

Figs. 3 and 4 are fragmentary cross-sectional views of the invention with the section being taken along the line 3-3 of' Fig. 1, with the handle in positions spaced 90 degrees apart and a set of contacts in both closed and open positions.

Fig. 5 is a cross-sectional view taken along a diameter of my improved switch, with the handle in the position of Fig. 4.

Fig. 6 is a plan view of the invention, partly broken away.

Referring to the drawing, my invention comprises a base I!) of insulating material, substantially in the shape of a cylinder, having a peripheral shoulder l2 provided by an enlargement of the base to enable the base to be mounted conveniently within a circular hole in a mounting plate or part of an electric range l4. For the purpose of receiving a disc cover l6 of insulating material, the top of the base I0 is hollowed out concentrically with the axis of the base. The cover I6 may have a diametrical handle portion l8 extending upwardly therefrom and may have a metallic spindle embedded therein and extending from the underside of the cover through a bore 22 in the axis of the base.

In order that the handle may be rotated into four positions and maintained therein, indexing means in the form of spring-pressed balls adapted to seat in recesses in the underside of the cover are provided. The balls 24 are normally pressed outwardly of circular borings 26 by compression springs 28. The borings' 26 may be conveniently placed in diametrically opposite positions on opposite sides of the spindle 20. The

balls 24 are normally pressed into one or another of four segmentally-shaped depressions 28 in the underside of the cover 16. These depressions are preferably spaced 90 degrees apart. In order to hold the cover upon the base against the action of the springs 28, any suitable securing means may be provided on the end of the spindle 2B.

The current carrying parts of the switch comprise four pairs of fixed and movable contacts which are concentrically arranged within the base. The movable contacts comprise arcuate strips of flexible sheet metal 40, 44, 48 and 52. Each of these arcuate contacts is mounted within an arcuate recess (see, for example, recess H for contact 4!!) formed in the floor of the base. One end of each of the arcuate contacts (see, for example, the end 49 of contact 48) is oifset downwardly to rest upon a ledge 54 in one end of the arcuate recess in which contact 48 lies, and be held thereon by a screw bolt 56. The bolt 56 may pass through the base and engage with a wire terminal 58 for the purpose of connection of the wires of an electric circuit thereto. In a similar manner, the arcuate contact 44 also is secured to that same terminal plate 58. In

like manner, the contacts 46 and 44 are connected to one wire terminal 59.

The free ends of each of the arcuate contacts are offset downwardly (for example, see in Figs. 3 and 4 the end 50 of the contact 48). On each of these free ends there are mounted contact buttons or surfaces of silver or other suitable contact material. (See, for example, contact 5! in Figs. 3 and 4.)

The contact buttons on the free ends of the contacts are each normally urged, by the resilient nature of the contact, toward engagement with a fixed contact. The fixed contacts are mounted on metallic contact-supporting plates, in similarly placed positions on opposite sides of the axis of symmetry. Specifically, plates 60 and 64 are similar and plates 68 and 12 are similar. Each is held in position by a bolt passing through the base and taking into a terminal plate on the bottom of the base.v The bolts of plates 60 and 68 take into the same terminal plate 61 (Fig. 5).

The fixed contact buttons are mounted on the underside of the part of the contact supporting plate that overhangs the end of the cooperating resilient contact. See, for example, button 69 on contact-supporting plate 68.

In order to cause engagement and disengagement of the buttons of the stationary contact plates by the buttons of the resilient contact members, cam portions are struck upwardly out of the surface of the resilient contact members. These contact portions are pressed up from one edge or the other of theresilient contact members so that no cam surface of any contact member is the same radial distance from the switch spindle as the cam surface of any other contact member. For example, the cam surface 48c of the contact member 48 is pressed up from the inner edge of that contact member, while the contact surface 52c of the contact member 52 (which is co-axial with .contact 48) is pressed up from the outer edge of its contact member.

The resilient contact members are held in open circuit position by engagement of the cam surfaces thereof with the bottom of the disc cover l6. Inorder that the resilient contact members may engage with the stationary contact members, cam recesses are formed in the underside of the rotary cover it: to receive the cam surfaces (see, for example, 480 in Fig. 3 received within the recess 481'). Referring to the several reces'ses formed in the underside of the cover as illustrated in Fig. 2, it will be noted that they are located at four difierent radial distances from the axis of the cover or spindle, the recess 581' being the closest to the switch spindle.

From the foregoing, it will be apparent that as the cover is rotated, the cam surfaces of the various resilient contacts may seat at proper times within the various recesses in the underside of the cover provided for them so as to cause various combinations of the contacts to be engaged or disengaged in order to establish and dis-establish various circuit arrangements.

By reason of the different radial distances of the cam surfaces from the axis of the switch, and by forming the cam recesses in the underside of the cover, I have been able to make a very com pact switch using a minimum number of parts which are all adequately insulated from one another as circumstances require. It will be apparent to those skilled in the art that a slow break switch of this type is particularly useful in connection with alternating current work, although it could be used in direct current work in cases where the voltage and current requirements were sufiiciently low.

As shown in Fig. 6, the cover I 5 may perform the function of a dial, having legends indicating High, Medium, Low and Off positions of the switch as the legends come opposite a pointer on the casing Hi. The cover is, thus, an operating member and an indicating dial as well as a cover, and since it has that triple purpose, it reduces the cost and number of parts necessary to make up the switch.

Modifications within the scope of my invention will occur to those skilled in the art. Therefore, I do not limit it to the exact details of the preferred embodiment illustrated.

I claim:

1. In an electric switch, an insulating base hollowed out to provide a circular cavity, an insulating cover manually rotatable in said circular cavity, concentric arcuate recesses within said cavity and separated by insulating walls, fixed contacts in each recess, arcuate resilient contacts in each recess cooperating with said fixed contacts, cam means on said resilient contacts each being a difierent distance from the axis of rotation of said cover, camming means on said cover at different distances from the axis of rotation to actuate said contacts selectively, said cover oooperating with the walls of said recesses to form separate closed chambers for cooperating pairs of fixed and movable contacts, and spring pressed indexing balls located in the central portion of said base cooperating with said cover to locate the cover in its several positions.

2. an electric switch, an insulating base hollowed out to provide a circular cavity, an insulating cover manually rotatable in said circular cavity, individual recesses within said cavity spaced difierent distances from the center of said base and separated by insulating walls, fixed contacts in each recess, -resi lient contacts in each recess cooperating with said fixed contacts, cam means on said resilient contacts each being a different distance from the-axis of rotation of said cover, camming means on said cover at difierent distances from the aixs of rotation to actuate said contacts selectively, said cover cooperating with the walls of said recesses to 'form separate closed chambers for cooperating pairs of fixed and movable contacts. j

3. In an electric switch, {an in'sulatingnbase hollowed out to provide a circular cavity,an .i nsulating cover manually rotatable in said circular cavity, individual recesses within said cavity spaced different distances from the center of said base and separated by insulating walls, fixed contacts in each recess, resilient contacts in each recess cooperating with said fixed contacts, cam means on said resilient contacts each being a different distance from the axis of rotation of said cover, camming means on said cover at different distances from the axis of rotation to actuate said contacts selectively, said cover cooperating with the walls of said recesses to form separate closed chambers for cooperating pairs of fixed and movable contacts and indexing means located in the central portion of said base to locate the cover in its several positions.

4. In an electric switch, an insulating base hollowed out to provide a circular cavity, an insulating cover manually rotatable in said circular cavity, concentric arcuate recesses within said cavity ate said contacts selectively, said cover cooperating with the walls of said recesses to form separate closed chambers for cooperating pairs of fixed and movable contacts.

5. In an electric switch, an insulating base hollowed out to provide a circular cavity, an insulating cover manually rotatable in said circular cavity, individual recesses within said cavity separated by insulating walls, a fixed contact in each recess, a resilient contact in each recess movable in a direction parallel to the axis of rotation of said cover, cam means on said resilient contacts spaced unequally from said axis of rotation, camming means on said cover at different distances from said axis of rotation to actuate said contacts selectively, said cover cooperating- 

